This application seeks funding for a pilot project that will allow the PI to chart a new direction in research. The PI is a productive Professor of Biology in the Department of Biological Sciences at Chicago State University, a minority-serving institution. The PI was recently introduced to the model organism Dictyostelium discoideum and has been using this organism to introduce students in classrooms and summer workshops to basic cell biology research. This experience has inspired the PI to establish a new research program that builds upon his experience in the cell biology of endocytosis and phagocytosis. The innovative screens of Dictyostelium mutants proposed here will immediately establish a new lab setting in which to mentor students and set a new research agenda for the PI. The PI aims to establish his presence in the Dictyostelium community, and gather preliminary results that will support proposals for funding from mainstream extramural sources. Phagocytosis, or cell-eating, is a complex process carried out by many eukaryotic cells, especially those of vertebrate immune systems. It is especially important to understand how phagocytic cells respond to the variety of microorganisms they encounter. Dictyostelium is a professional phagocyte and is the only model organism that allows forward genetic approaches to studying the fundamental cell biology of phagocytosis. Two novel fluorescent assays are proposed that will be used to screen Dictyostelium mutants for defects in signaling during phagocytosis. Dictyostelium cells will be mutagenized by restriction enzyme-mediated integration (REMI) of a plasmid expressing a selectable marker. In the first screen, Dictyostelium mutants will be pulsed with fluorescent bacteria and sorted for cells that cannot degrade the bacteria. For the second screen, a Dictyostelium cell line will be constructed that fluoresces upon induction of the prestarvation response. Dictyostelium mutants will then be screened for inability to inhibit this response in the presence of bacteria, their primary food source. These assays will identify novel genes involved in intracellular signaling during phagocytosis. Because phagocytosis in Dictyostelium is necessarily linked to decisions regarding cell growth and differentiation, we expect to establish Dictyostelium as a model system for investigating cellular mechanisms that integrate nutrient sensing, metabolic regulation and development.